Automatic telephone system.



A. H. DYSON.

AUTOMATQC TELEPHONE SYSTEM.

APPLxcAnoN man Nov.13.1so5.

Patented Mar. 2G. 1918 6 SHEETS-SHEET 2.

A. H. DYSQN.

AUTGMAUC TELEPHN SYSTEM.

APPUCAUON min NovA n3. 1906,

1,260,971. m0111011 Mar. zu, uns.

6 SHES--SHEET S. ai ul;

A. H. DYSON.

AUTOMATIC TLPHONE SYSEM.

APPLICAHON FILED OV. 13, i906. 1 ,260,97 1. Patented Mm. 26, 1918.

G SHEETS-SHEkE 4.

A. H. DYSON.

AUTOMATIC TELETHUNE SYSTEM.

APPLICAUDN FSLED NOV.13| |906.

Patented Mar. 26, 1918.

6 SHEETS-SHEET 5- A. H. DYSON. AUTOMATIC TELEPHONE SYSTEM. APPLICAHQN man Nov. 13. usos..

1,260,971. Patented Mar. 26, 1918 6 SHEUSfSHEET 6.

K I O .I 'u'. i z-hmh *a o o Q u., s Q* in F 3 -M I www lllmrTnio STATES PATENT OFFICE.

ALFRED DYSON, F CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 XELLOGG SWJITCIl-IBOAIM)y SUPPLY COMPANY, A CORPORATION OF ILLINOIS.

AUTOMATIC TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Mar. 26, 1918.

Application filed November 13, 1906. Serial No. 348,255.

. To all whom t may concern:

4Be it known that I, ALFRED H. DrsoN, a. citizen of the United States, and resident .of Chicago, Cook county, Illinois, have inrarily associating the first selector with the calling line by means of automatically controlled apparatus.

In general, the object of my invention is to produce a simple and reliably operating structure of the described character. I have riven special attention to the method Wherey the various switches employed in the connection are released when conversation is finished, dividing the control of the releasing mechanism between the calling and called subscriber in such manner that the called subscriber has sole control of the release of the connector as soon' asconversa-` tion between the subscribers has commenced; whilethe calling' subscriber, under such circumstances, has sole control of the line selector, first selector and second selector. Previous to the commencement of conversafion. however, the calling subscriber is enabled to release all switches including the connector.

Another object of myinvention is to provide mansincludcd in the telephone system vfor registering the number of calls made over caclrline, as a calling line, to which a, response of the calledsubscriber is received. This I accomplish by associating with each line sclectornleclmmsm. a printing magnet Vactuated when the called subscriber answers the call, together with an adjustable typeframc automatically adjusted by the operation of the line selector in connecting to the calling line so as to bring a type, bearing the number of thecalling subscriber, into operative relation to the'printing magnet.

The above, with other advantages of my improved system, will appear and be pointed out more specifically in the detailed description of the drawing and in the claims.

Figure 1, comprising; arts 1,"2.'and 3, illustrates diagrammaticfxlly a preferred circuit arrangement; Fig. 2 is a. front View of a master-switch; Fig. 3 a side view thereof; Fig. 4 is a sectional view of a line selector, showing particularly the primary magnet and its associated mechanism; Figs. 5 and 6 show a first selector release magnet and associated mechanism; Figs. 7 and 8 show top views of an over-run and lrimary olf-normal switch, respectively; jigs. 9, 10 and 11 are respectivelyflet, front and right elevations of a line selector. Figs. 12, 13 and 14 show similar elevationsof a connector. Fig. 15 is a top view of the registering mechanism of my invention.

Referring first to Fig. 1, the system there illustrated may be considered as a ten thousand line system. y i Assuming such to be the case, each subscribers line such as those 'of Vsubstations A and B, extendsto the exchange and is there provided with its individual passive multiple line contacts 20, 22 and 24 appearing` with those of ninety-nine other lines lin the contact banks of ten line selectors suchas D. -Inasmuch as ten thon'- sand lines are assumed` there will have to be in all one hundred such groups of lincs,`

each with its ten line selectors, making a total of one thousand such selectors. Each such line selector has permanent connection with a particular first selector such as E, which is automatically brought under the control of currents to be sent over the calling line bv*y the operationr of the lir` selector The first selector by its adjustable wipers. gives the callingr subscriberaccess io one hundred second selectors, there beingten of these representing each one thousandA lines of the exchange. Contacts of thesecondV selector engaged by the first selectors are. of course. multpled in the usual ner. to alarge number of first selector colifact banks and would ordinarily be multipled one hundred times or to one' hundred `such b'anks.

Responsive te currents transmitted over Vthe calling line by the subscriber, the rfirst selector is caused to select thegronp of sec-l ond selectors corresponding to the one thousands digit of the called numbe; thefl selector then automatically selects .the first idle second selector olf the selected group, placingr il under the control ot the calling line.

The second selector, by its wipers, gives acct-Ps to om` hundred connectors divided in Ien groups ot' len switclnfr each, the ,writeln-s` of each group being adapted to select out any particular line ol a one hundred line group of subscribers to which the switches of the group are assigned. The contact terminals of the coni-meters are, oi' course, multipled a large nlunber of times and would ordinarily be multipled in the 'present systern one hundred times or to each second selector of a one thousand line group.

The Second selector operatingr responsive to currents controllcdat the calling subslation, selects the group of connectors desired, and then the idle connector. thereby placing it under the control of tlu` calling substation.

The connector. by its wipers, has access to contacts forming multipleterminals of subscribers lines forming a one hundred line group, said contacts being multipled teu times to appeal-.iu the contact banks of ten connectors.

Tn an ordinarily busy exchange of ten thousand lines, one thousand lino selectors with their one thousand first selectors, one thousand Second selectors, and one thousand connectors, would be adequate to handle the business of the exchange.

As above indicated, line selector D by means of its wipers has access, to one hundred .sets of multiple contacts '20. 22 and 2 4 forming terminals of a group of one hun* dred subscribers lines. The contacts of these lines are preferably arranged in ten groups of ten contact sets each, the motion of the wipers of switch D being first in a primary direction in one plane to select a group of contacts, and then in a secondary direction in another plane to select the calling line of the group. Each group of ten lines therefore, has a common or group contact 26 controlled by a common relay 18,

which contact the wiper 27 engages. The said wiper 27 controls the primary morcjment of the switch D, the line Wipers 21,

A23 and 25 moving along with the said Wiper 27. Vhen the wiper 27 reaches a group 'contact 26 belonging @to -a groupA of ,lines lamong which a-callin .line is included, the

primary movement o `all the` wipers is arrsted and the line wipers 21, 23 and25 vthen itutlate their secondary movcmentsto select the individual contacts 20, 22 and 24 of the calling line, wi er 27 remaining quiescent at this time an not partaking of the seconder movement. V As be ore statcd, each group of one hundred calling lines has associated with it ten line .s electorsfD, so that the contacts 2.0,` 22

and 24 of each line and the group'contaet.

.t ol.' each group is inultipled ten limes, once to each such lino selector bank. When the calling subscriber removes hisl ifm-elven', lncauses a line selectin lo start into opcration to seek out his line and thereby connect the first selector with said line. Thi` is effected through the agency of the master switch C to whose relay 28 cach calling lino is enabled to transmit currcntby means oiE the switch contacts ot' its line relay 9. The said master-switch when operated at the initiation of a call as above indicated, cause;` an idle line selector to start its operation. The line selector then re-acts upon the iaastcrswitch in such manner that its wipers iO-3d more away from the switch contact-= 3l-35 of the line selector which they start, and then keep up an independent progressive movement ria terminals fil- 35 of busy line selectors until they reach terminals of an idle one, when the said wipers come to rest. The detailed relation of thc dii'l'erent parts to one another will be best understood through the narrative ot operation.

Assuming that subscriber A is to be connected with subscriber B whose telephone number will be assumed to be 3456, subscriber` A first removes his receiver thereby completing a conductive bridge of limbs P and S by the usual elevation of thc hook lever. Relay 9 is energized by current from ground therethrou h, normal armature contact 14 over limb Ig through hook lever and transmitter at station A, limb S, normal armature contact 16, to battery B. Armature 10 is thereby attracted tp'cngage its switch contact, (immediately thereaer breaking the normal contact of said switch contact whereby substation control of relay 9 is removed) to complete a locking circuit for said relay established from ground therethrough, contact 10, contact 17,relay 1S, to battery. Relay 18 attracts ,its armature to remove ground from the multiple group contact 26 at cach line selector of the ten. Armature 11 disengagcs 'its normal contact to removev ground from each of the individual private contacts 20 of the line at the ten line selectors, and thc said armature engages its alternate Contact -operatively connecting relay 12 with the contacts 20. The lower armature off relay 9 engaging its` contact, completesy a circuit from ground through resistance 19, the left-hand winding of master-switch relay 28 to battery, causing said relay to attract its armature and complete an'energizing circuit of relay 29 y which la'tter attracts its armature and causes l [lll IUT) and closes circuit from, ground throu h resistance 36, right-hand winding of re ay 28 to battery, whereby the armature of relay 28 is allowed to fall back, because the said relay is differentially wound, and resistances 36 and 19 are equal. It is apparent that relay 29 is thereon immediate] denergized and its armature retracted. i rmatur'e 35) of rela 37 is attracted closing circuit through vi ratory primary magnet PM, which becoming energized, advances wiper 27 to enga e t e first group contact 26, Wipers 21, 23 an 25 moing opposite the contacts ol' the first group'fbut not engaging any contacts. Relay-37 has attracted its armature 38 and if the first group contact 26 engaged is in its Anormal condition, no line in the group th'en calling, the said contact will be grounded at the armature of group relay 18, and locking circuit is completed for relay `37 from battery through said relay, attracted armature 38, contact 27-26 to grodnd via armatiire of the first group relay 18. As armature 39 thus continues attracted, magnet PM is, on the retraction of its vibretory armaturc, again energized and moves wiper 27 to engage the second group contact. If this contact has its normal round at the second grou relay 1 8, relay 3 will continue ener- 30 gize and the preceding rocess is repeated; wiper Q7 engaging the tliird group Contact 26; and so on until the group contact of a calling line, that of subscriber A is found avhosc ground has been removed by the pre- ?.5 viens-ly described operation of relay 18. No locking circuit for relay 37 is then completed and its armatures are retracted, the' armi ture 3i) preventing further operation of pri- :mary magnet PM whereby wiper 27 rests n) engagin group contact 26 of the ten line 'group including line A, while line wipers 21, 23 and 25 have moved along with Wiper 27 to such a position that they are adjacent to the group oi' contacts including a line contact set of subscriber A. i y

0n the first primary movement of the wipers, contacts 40-41-42 of the primary off-normal switch P. O. SW were shifted to their alternate positions, contact 40 o'4 ening the original energizing circuitl of re ay 37.

Contact 41 completes a circuit from round,

through contacts 3-'34,lrclay 32 to attery B causing relay 32 to attract. its armature whereby circuit is completed for magnet 33 of the master-switch, Whichfby its energizetion, advances Wipers 30 and 34 a. step to engage contacts 311-35, respectively, of the next line selector, it bein understood that the said Wipers have in ront of them ten au contacts 31 and ten contacts 35, belonging in pairs to ten line selectors. Ifthe contact 35 now enga ed by wiper 34 belongs to a busy line se ectcr, that one in which s ring 41 has been shifted, elay 32 will continue energized by current from this second line selector via iis'shifted spring 41; magnet 33 will step wipers 30-34 one step farther, when thc above process will be repeated if that line selector is in use, and so on4 until Wiper 34 enga rcs contact 35 of an idle line selector, when its contact 41 will be as shown at- D. namely, on open circuit whereupon relay 32 will become dcnergized preventing further operation of magnet 33, and wipers30 and 34 of the master-switch will remain on the contacts of an idle line selector u'aiting for another call to come in.

Returning 1 now to primary oit-normal switch contact` 42. its shifting operatively connects the winding of relay 48 with the normal contact ot thc upper armature of' relay 37, so' that on the dencrgiziition of said relay occurring as before described, circuit is completed from ground at said upper armature, through contact 49, normal con- ,tact 45, rcla}r 4S to battery B. Relay 48 is thereby energized 'to initiale the secondary movement of wipers :7.1, 23 and 25 hy means of its armature 51 which closes circuit from battery through secondary magnet SM,arnia turc contact 51, to ground through alternate contact of Vswitch spring 4G, springs 4G-l7 of the release switch BSW having been previously shiftedV on the first energization ot' primary magnet PM, lVipcrs .21--23- 25 eengage contacts 20-22-24 respectively,

belonging to the first line of the group. Whenlit is at normal, that is, when the subscriber is not making a call, its multiple contact 20 will be grounded by Way of the normal contacts 1l and 15 of its relays 9 and 12; hence, armature 50 of relay 48 bein at this time attracted, a locking circuit Wi l\be closed from grounded contact 20,'

wiper 21, attracted iii-,mature 50, relay 48 to battery and armature 51 continuing attracted, secondary magnet SM, will, on the r retraction of its armature, became again euergized moving wipers 21-23-25 to engage contacts 9,0#22-24 of the Second line of the group. If this line is not calling, it s contact 2O will be grounded and relay 48 will continue to be locked as before described, a third dcncrgization and energization of secondaryinagnet SM resulting, advancing the wipers the third secondary movement, and so on until' contact 20' of the line of subscriber A is reached` which contact on account of the attracted condition` of armatori` .l1 of' relay 9, is uugroundcrl, whereby locking circuit of relay 48 is destroyed, its armature retracted, opening. circuit of secondary magnet SM andprcyenting further mo'vc- Incnt of Wipers 2,1-,239 5 which remain in engagement, with the multiple contacts ot the calling line. Armatures 49 and 52 were held' attracted'during the secondary more ment of the wipers in order that wipers 23 rand 25. which were then wiping over line contacts of tht1 variouslines, might be insaluted so that no disturbance of existing ifonxersatiolis could occur. Upon the denr-r, 'i7.atiou ol 'the relay 48, they will of course be reina-lod to extend wipers 23-25 lo connection with the circuits of the first scheel-cr ll. Contact 50, upon the dcnergization of the relay, falling back t0 its nor mal grounded contact, completes a circuit from grounded cout-.uit 50, contact- 21--20 and alternate. contact 11, cut-olf relayf12 t0 battery ll. energizing the said relay 12 which, by the operation of its armature 13,

completes a lockingl circuit for itself to the same ground at contact 50, while armature lo wiper 23. Armature 15 removes t e lground 'from the normal contact of armature 11 of relay 9, thereby preventing a permanent locking of relay 12 which would otherwise occur when a connector engaged @renew 0f the lili@ Armature ln its operation, opens the normal connection oi battery B to limb S :und completes the circuit of said line limb through to wiper 25, while arlnahu'e 1T opens the previously extending series circuit through relays 9 and 18, causing the dencrgization of both oil Vthem and'i'he retraction. of their armatures, that of relay 18 again grounding group Vcontact 26. Since ground at armature 450 of relay 48 is now connected to the private contact 20 individual to the line, its multiples are now nou-selectable by any other line selector.

The secondary off-normal switch S. Sw contacts Afl-45 were shifted at the iirst encrgization o'f the secondary magnet SM, spring 45 interrupting the original energizing circuit for relay 48, while sprinv Llll 1uterrupts a neutralizing circuit inclu ing resistance 36 hereafter dcscribmi` and said spring 4,3 by engaging its alternato contact, operatively associates relay 4S `with the normal contact of release switch spring elrfor use in the restoration of the line selector, as 'hereafter deccrilriod.

It `will be observedthat upon the retrac- Jtion of the armature of relay 37, which in its attracted position originally completed the neutralizing circuit for relay 28, a new path for continuing such neutralization had been completed `by the shifting of `switch sprin 46 occurring on the first actuation of primaryv magnet PM, the new neutralizin circuit extending from the ground of said switch spring, 4,-(5, its alternateicontact, normal contact et? switch spring 41h-and resistance 36. This circuit is of course broken on' the rstenergization of secondary magl net SM by the shifting of spring 44, but before that occurred, 'a third circuit was completed from ground at switch spr-iugm, itsalternate Contact. attractedV armature 51 of relay 48 and resistance 36. This last cir 65 cuit continued until the, denergzation of Lll) 14 completes a circuit from limb P throu h relay 48, when the circuit of resistance 86 in the right-hand winding of relay 28 isi opened at contact 51; but simultaneously with the openin of this circuit, relay 12 was operated an rela-y 9 denergized, the retraction o'f the lowerarmature of the latter openin the` circuit through the lefthand winding of .relay 28. Thus, it willV be observed that from the time the line selector starts, armature of rela 28 will remain` retracted as far as line and switch D are concerned,first because of the neutra-bred condition of the Jrela windings continuing until selection of the ine, end'thereefter because of the practically simultaneous/opening of the neutralizing circuits of its windings. Thus .an untoward attraction of its armature .is prevented which, should it oecur or exist after `Wipers 30 and S-ihavc reached contacts 31-35 of an idle line selector, Would cause the initial operation of said selector toile avail, as there would be no calling line dor it to make connection with.

The relation of the master-switch to the line selectors andthe calling lines which it serves, is'such that as many line selectors, will be started lto seek out calling lines as calls come into the exchange, and no more, except in certain rarely occurring instances. It will be observed that if three calls were to come in simultaneously, the resulting energization of the three relays 9, of theilines will cause three resistances. 19 to be connected in circuit with the left-hand Winding of relay 28, causing a greater current to :lowv therethrough than in the case of a singie call. The4 starting of the frstl line se lector throwing only one resistance 36 into circuit with the right-hand Windingwill neutralizeonc only-of these windings 19; therefore, the armaturev of relay 28 will continue attracted. and as Soon as the wipers 30 and 3311- rc'ach contacts 31 and 35 of the next idle line selector, this switch Wil lalso be started; there will then be two wi`ndings incircnit `with the ri lit-.hand winding of relay 28, but there being three windings in circuit with the leflhand winding, its armature will continue attracted, and when Wipers 30 and 34 reach the third idle line selector, this one will also be started in search of the third line. PAe soon as this, switch starts, however, a'thrd windin 36 will beicluded in circuitfwith the right- 120 hand 1ylnding of relay 28. The three windings 66 will effective y neutralize thethrce f wlndings 19, vthe armature ofrelay 28 will be retracted, and when Wi ers :3b-'34 engage contacts 'of e fourth i lefline selector, 25 this switch will not best'arted.

One of the rarelyfoccurrin g instances above referred to where more than the re uied number of line selectors will be starte may be imagined as follows: Suppcsefthatthe 180 Landon positions of w i ers 30 and 340i the master switch are suc that the first and second steps will cause them toI engage contacts of idle lineselectors. Let,V it be also supposed that a call comes in from a line whoseindividual contacts are the 9th contact sets of the fifth rows in the line selector banks, and that a call simultaneously cornes in from a line whose individual contacts are located in the seventh group. o row of contacts. In' such cases, a line selector D would start. j Its starting would throw wipers 3,0-34 upon the contacts of the next luie selector; relay 2-8 continuing'energized owing to the inclusion of two windin s 19, one for each calling lie, would cause tis'second'line selector to instantly start, and the two line selectors would be simultaneously performing their primary switching movements, the second one perhaps two steps behind the first one; Arelay 28 being then neutralized. The first lineselector would reach rou`p 5 and its wipers start their "secon ary movements along the group havifg nine steps to erform before reachin thecallinv line. ntil the said line is reac ed,the se ectable character of contacts 27 and 20fwould of course continue. Obviously, the second line selector would reach -the group contact of group five before the wipers oithe first one reached' the ninth contacts of the sa-id group, and as a rc"1lt, the wipers of. the second line selector would begin 'wiping along the fifth row in search of the line contacts of the calling line. But the rst line selector being two steps in advance would reach the contacts of the calling line first undV renderlthem unselectable so that the second line selector would continue, passing the said contacts to` be released when it reached the end oi-the group b means of the Switch sping aigu arran yc in the switch mechanism as to' be shifts when the line selector is over-rung on its secondaryV movement. In the meantime, wipers 30-34 have been moved to en' fa e the contacts oil the third line selector. v

\i`h1s line selector has not been started since the armature of relay 28 was retracted. .Asy

soon however as the second line selector is released, its windin 36 is removed from circuit of relay 28 an `windng 19 ofthe sec ond calling line is therefore again effective to attract the armature of relay 28 and causes the operation of the third lne seleclor, which proceeds in its orderly o eration to select the second calling line. ethu's have three line selectors operating to connect first selectors with the two calling lines. Taking into consideration the various factors necessary for -rthe occurrence of the i 'above described operation, it is `apparent that even in the case of calls simultaneously comin in from a single group ofone hun` dred nes toits master-switch, the above operation will very rarely occur.

The amount of time required for the operation of the line selector to connect with the calling line is excccdingl small requiring, (as will be more fui y understood, when the mechanical features of lheswitches are described hereinafter) a maximum of thirty step-by-step movements under the most unfavorable condition, the Switches being of such character that this number of steps can be performed in less than one second oi time.

. Subscriber A desiring his line to be conncctcil with the line 3456, now operates calling device to transmit three impulses of current, by rotating the said device clockwise until three of its insulated teeth have passed below spring 3 and thenreleasin it whereon its associated spring turns the ial in the opposite direction, the three insulated teeth eac causing spring 3 to engage and 85 "disengage its contact once. With Vthe return mate contact temporarily condauctively dis- -unitin the two line limbs P and S at that point 1n order that impulses may be sent over the line limbs separately. The operation of the dial as described, sends three im?L pulses of current fromA ground atthe subI station through spring Siandjtts contact, over limb P of. thq,line`,through httracted armature le, -contact' '22a-23, armature 49, L05

f contact 5 at switch E, uppe jarmature of 1.1'elay73, contact 55, through thle winding of primary relay PR to battery causing the energizations and denergizations of said relay whose thrice. attracted armature, causes three impulsesr to flow from ground through armature spring 57 and its alternate contact, contact 5 8, primary magnet PM', to batter The three resulting cner- A gizations of M move the first selector switch wipers 59-'60-61 to positions adja- .cent to the third group of second selector contacts, terminals of second selectors belonging to vthe third thousand 'lines including those from 3,000 to 3,999; With the first primary movement of the wi ers, the 4 primary off-normal switch P. 0. gw contact,'andthe release switch RSW contact, are shifted to their alternate positions preparatory to the energization of the seconda magnet SM. j l

ith the return of the -dial 'to n rmal, an impulse flows from ground at `th substation throughl spring 2 and its contact over limb S of the line, through attracted arma- '130 ture 16, contacts 2li- 2.5, contact 52, through contact 62 at switch E, lower armature of relay 73 contact 64, winding of lsecondary net SM. to battery. The secondary magnet l having.` u vilbratory circuit, attracts and ret leases its armature, the operation boing c'ecshould the wipers oflanolgher lirst-s ment with contacts 8G8T-.88 of the first second selector of the group. With Lthe first secondary movement of the wipers the secondary..ollnormaliswtch. S.. 0.-. tw" .95.11

tacts :B8- 66 are shifted to operatively disconnect the windings of the primary-magnet PM andof the busy relay BR Yfromi switcln springs 57 and 65, respectively. Il the sccond selector mentioned 'is idle', it will he in thecondition shown yin Fig. 1. Contact 86 bein on open circuit, busy relay BR4 hel comes teinergi'zed, armature 68 opens the circuiti of magnet SM', and the wipers rest in engagement with thecontacts of the first second' selector; armatures 67470 bytheir retraction render the said second selector responsi'v'e to current to be transmitted by relays PR and SR;`

Armature G8 nr engaging its nornial con" tact, places direct ground through the primary off-normal switch-I. O. Sw and re` lease switch BSW contacts', normal contact 68, right-hand armature of RM and wiper 59 upon contact 860i the second selector-and its m'ultiplesfto render the ysaid Se?. 'lector busy. It will therefore, result that am now be brought to engage multiples .of cog# tacts 86-87-488 olf. the rstsecond select vr switch F, busy relay 13R"` of this. other first selector then. energized will have its circuit continued inthis condition hy current ,ow-

'ing from grounded contact 86 to its multile engaged, tneright armature Contact of R through attrait-:teal armature v69, 'of its busy vrelay BR', through said relay to battery. The -rclay will therefore@v l continue to be energized. Secondary .magnet SM 'by the retraction of its armature will have its circuit closed and become `energinod and deenergizeda second time, moving the 'wipers 55)-60-61 to engage the contacts of theseeond second selector of the group'. If this be l in use, another locking,r circuit for busy relay BR will be'established asthe preceding one is broken; SM aduanres the Wipers a third saifl rel:1y is operated four tunesl transV lnitting: four current impulsos from ground through alternate contact 57, normal con-l tact GT, contacts 60e-87, normal contact.l S9,

normal contact 91, primary magnet lfMz.'

to bntlcnr,` causing 'four energizations of tho said primarymagnet.A The said magnet thereby moves wipers 93-94-95 of the second,sclcetouadjacent to a group of contacts, terminals of connectors Vbelongino to .the

fourth one hundred group of suliscribcrs` lines of the thi-rd thousand, this including lines from 3,400 to 3,499. lVitli the first lnoi'eiet ofitle Wipis, the primar ofinoriual switch `Stl-i1ltl.l LQ- SW, are .S lifted to their alternate positions and also the spring of the release switch. RSWLZ.

With the return .ci the dial to no1-nml, `a single im ulse Hows from ground at the sub.- station tnjough relay SR over `the before traced path, said `relay being energized and denergzed to transmit Ta. current impulse from ground through spring Y65 and its alter-l nate contact, throughnormal contact .10, contact (lL-88, contact' 90, `busyl relay BR', to

battery, energizingtheeaidgrelay. Its upper armature and armature 98 p'lace wipers 94 and 955011 operr'circuihcwhxle armature 96 completos circuit from gound at the pri,- mary olf-normal switch 0. Swlthrough the'altcrnate release switch BSWE contact, attracted armature '96.. and the 4winding of secondaryiid/11"V to battery. causui .the energizteuietsei .um etwllich is crectlve to cause wipers :951:0 engege @mais aast@ sismiche ara. con- `nctorfftle finite. group Ifcon' .t `99 belongs, to insidie connector, itwill on open circuitos .shown at'G in Fig." l No lookin l circuit or' rela` BR will msult from te .attractie oiga intuire 97 ,and lthe ,armaturcof saidr'elay falls back,itl1e .upperf necting the circuits' of th amature andY armature 98, operativelymone connecter with relays PR and SR, rendering. the connectorcontrollable from substation A, while armature 96 opens the circuit of.secomlaxy,magiv net S'M, leaving the wipers in engagement "with the terminals of thelfirst cnncctorof 1the group, and, by the engagement fof eits alternate contact, said armature Q-Lplalces deadv ground from the primal? n -no1-m11 Switch spring, alternate ,contactirlclease switch iRw. normal contact. gnemal contact of the right? er ofrelease magnet RM2, contact 93-99 upon the multiples ot the said contact 99 appearing at the other second selector banks, so that if another second selector F has its Wiper 93 brought to engagement with a multiple of contact 9-9, its relay BRz will be locked by current from grounded contact 99 via alternate contact 9T; secondary magnet SM2, then advances the Wipers to engage contacts, terminals of the second connector of the group. If this contact 99 belongs to an idle connector, the second selector will stop its sccondary movement and the Contact 99 will be rendered busy as described in connection with the second selector F, so that a third second selector seeking a connector in the same groupnvill select the third connector of a group, and so on.

With the first secondary movement of the wipers 93, 94, 95, springs 89-90 of the secondry olf-normal switch S. O. SW2' are shifted to, operatively disconnect primary magnet BM2 and busy relay BR2 from relays IR and SR.

`Subscriber A now operates dial I transmitting five impulses of current from ground at the substation through relay PR, causing five actuations thereof, which are effective to transmit five' impulses of current from ground through alternate contact 57, contacts 67, 605-87, 94-100, normal contact 102, contact 103, through primary magnet PMS at the' connector G to battery. Five .resulting actuations of said magnet are efeotiv'e to move Wipers 105-106107 to positions adjacent to agroup of ten contact sets in their banks, forming terminals of the fifth group of the one hundred lines which the connector serves, namely: terminals of lines from 3451 to 3459 inclusive, followed b teri ininals of line 3450, itbeing understoo 'that zero is represented by ten current impulses. With the first primary movement of the wipers, primary oitnormiil switch spring P. O. SW3 is shifted to operatively connect contact 9,9, via normal. contact 122 .with the winding of the release inagnetlRll/ 3 to place the same under control of the calling 'scriben as will be hereinafter more fn l lained.

With the return of dial I to normal, a single impulse is transmitted after the last ot' the live preceding ones fromground over y exlimbS through relay SR, traversing a be.

fore traced path, ,actuatingrelay SR' a single time, whose armature. is effective .to transmit a single current impulse as fg)- lou's: from ground,c0ntacts 65,70,61,88; 8, 95, 101, normal contact 108, lower armature of in'ae'net RMa through secondary ma ie, Uirliobattcry. The secondary magnet 'S 3 is thereby actuated` a single time/'moving wipers 105, 1.06, 107 one step nearer the selected contact group, it bein understood tiri the normal positions of t e Wipers of a connector are such thz-t after any primary adjustment they are tu@ steps distant from the first contacts of the ,.soup selected.

' With the first secondary movement of the wipers, springs 102--l08 of the secondary ofi-normal switch S. (l. SW3 are shifted; 102, to engage its alternatirontact, while 108 is shifted only suiiiccntly to disengage its norinal contact; a second step of the wipers beingrequired to fiiitt it suiiiciently to engage itsI alternate contact. This arrangement of spring 108 is for the 'follon'in r purpose: to prevent un otherwise possib e premature operation of test relay TR which would occur were spring 108 completely shifted to relay SR`had its armature retracted', our rent would then pass l'roni grounded spring 65 of relay SR through alternate Contact 10S, lower armature of relay 109, left-hand Winding of relay. TR'to battery, which wouldrause the energization and denergizatio of relay TR and the consequent shitting;` of switch sprin fs 110 and 111 of the test switch. The shi ting of 111 would causejringing relay 112 to be energized Ato include generator 1n circuit with wipers 106--107 ,which should properly be on open vcircuit during theothcr secondary movements to connect with the called line.

Subscriber A now operates dial l to transmit six current impulses from gronn at the substation through primary rrlay PR, causing six actuntions thereof and six current impulses to 'be transmitted from ground via spring 5T, over the before traced lpath, contact 102, the impulses then passing' via alternate contact 102A normalv switch contact of Aupper arinatuie of relay 109` lower armature ofiinagnet lMa, secondary magnet SM3 to battery.` The [i1-st resulting' actuation of secondaryniagnet SMS moves 'wipers 105-106-107, now on their normal open circuit, to engage contacts 6, 'i' and S of the irstline ofthe group, or line 3451, and with this movement, the diniplcte shift:

-ing of secondary ofi-normal switchA springr before traced path to contact 108, thencevia its alternate rontact and the normalcontact of the lower armature of relay 109 through the irftfhand :grinding of test relay TR, to battery,causing the said relay lo attract its armatures. Let it be first assura engage its alternate Contact before secondary i that the called liuc B is idle, in which case :is :-,l|mv`i|, contact 0 is connected to battery l lhrougzjh the wiidiiig of cut-olf relay 12, 'lhci-e being no ground connection to the said Contact' except through battery. AThe attraction. 'of the right-hand armature of test relay TR connected its ri ht-liand winding from battery through said attracted armature, normal contact 101, normal Contact 110, wiper 105, to contact 6, butlsince this contact is already connected to battery, upon -the cessation of the impulse transmittod by secondary relay SR, test relay TR is deinergized, its armatures falling back this boing effective to shift spri-n 110 and 111 of the test switch TSW. -Tlise shifting of spring 110 connects ground to wiper 105, contact 6 and its multiples, completing circuit through cut-oil' relay 12 of called line B to battery. The resulting attraction of armatures 14 and 16 completes the circuit over limbs P and S of the called-for line to contacte 7 and 8. That of 14 also disconnects lim` relay 9 from limb P of the line,so that` when the callcd subscriber B removes his receiver, the act is ineffective to operate relay 9 which would otherwise cause a line selector to select his line. The placing of ound just described -upon contact 6 and iig multiples from spring 110, renders the called lic busy \ith res ect to other connectors as will lie herea ter more fully eX- plaincd, ground from contact G being also connected via armature 13 to contacts 20 of the called lin'e kifeping them unselectable in character. l

The shifting of test switch (TSW) spring 111, completes circuit through rela 109 from ground, spring 111, contact 115, ringing relay 112, to battery B2. On the resulting attraction of the armatures of relay 109, a circuit is completed from ground through normal contact of the lower armature of re lay 117, normal contact 119, attracted arma- Lure of relay'l, alternate Contact 102, concausing the energization of said magnet' 73 Whose attracted armatures complete a" bridge of battery B in the line of subscriber A from ground through upper windings of relays 74 ,and 75, attracted upper armature of relay 73, contact 54, to the left over the heavily marked conductor, Vto limb. P through the transmitter at the substation, returning over limb S and the other` heavily marked conductor@ contact 62, attracted lower armature of relay .7 3, lower windings ci, relays'75 and 7,4 to battery. Diilerenu tially connected relay 74 is not energized, the 'ow indi two"` windings being equal but cumulative y connected relay 75 attracts its armatures of which 56 and 63 complete parallel ,paths vfrom ground and battery to a6 limbs Ii and S respectively, while contacts y and 64 disconnect relays PR and SR from4 theV talking circuit.

Having explained the effect ofthe shiftingof spring 111 at G with respect to the firstselcctor, Ii will now describe its effect with respect to the culled line. lts shifting energizes ringing relay 112 over a before i traced circuit and the attracted armatures of said relay cause alternating current to flow from generator G2, upper armature of relay 112 contact 1067, alternate contact 14, limb l of the line of B normal hook switch contact, bell and condenser, limb S, alternate contact 16, contact 8, 107, attracted lower armature of relay 112,-1ower winding of relay 113 throu h battery B. The

interruptor I2 is provi ed in the, circuit of A Ytor current through the substation condenser does not actuate the relay. As soon, howev'er, as the called subscriber answers the call by removing his receiver, the substation hook lever engages its alternate contacteer pleting a conductively continuous circuit from ground through generator G2 or interrupter I2, as the case ma be, to limb P over the before traced path or ringin current, the alternate-contact of the hook ever and through the transmitter, r urning over the limb b and thence over t e before traced ath and the lower winding of relay 113 to iattery B2. Current flowing over this conductive circuit, energizes relay 113 whose attracted armature 114 first completes, by engaging s ring 115, a locking circuit including serially the already energized relay 109 and the upper winding of Velay 113 caus` ing both relays to remain'energized, the said armature immediately thereafter breaking the normal contactllftlereby eil'ectin the .dcnergization of ringing relay 112 an the Q,

enerator .G2 from The attruck immediate exclusion of connection with the calle line.4 tion of the lower amature and armature 116 of"rela 113 brid es relay 117 across the called-for ine, whic relay Vis, immediately energized by current owing over said line. The lower armature of relay 117 disengages its' normal contact whereb the before traced circuit through magnet 3 at E is inter-- rupted and the said magnet is denergized, the consequent retraction of its armature shifting springs 54-71 and 62-72 to their alternate positions. The denergzation of 7 3 does not e'ect 'the continued energization i'io of relay 75 on account of the parallel ath of current before indicated through sai relay. Springs 54 and 62 in disengping theii| normal contacts prevent relays y and SR from again being connected to the calling" line by the retraction of thearmatures of 73,

and in engaging their alternate'contacts, said springs- 54--62, complete the talking circuit of switch E. Sprin 72, in engaging its alternate contact com lates a path for energizing relay 76, whic relay by the attraction of its armatures 76 and 79 to engage their associated contact springs, thereafterbreaking the normal contacts of said springs reverses the connections of battery B to the calling line, causing a reverse How printing magnet 77 which thereupon by the aid of its associated mechanism prints the number of the calling line recording a completed call against it.

Returning nowY to relay 117 at G, havin explained the'eilect of the lower armature o said relay in disengaging itsnormal contact, it will be observed that the said armature engaging its alternate contact,conipletes a circuit rm ground through relay 118, said rela Y 118 by'the attraction of armature 121, esta lishing a locking circuit for itself through switch spring 110 of the test switch TSW to ground. Armature 119 completes the talking circuit to wiper 106; armature 120, closes a break in the circuit of release magnet RMS, 'while armature 122 in leaving its norm-al contact; removes Vthe reviously cxistin control of release magnet M from the cal ing substation, and by engaging its alternate contact, places an independent ground upon contact 99 and its multlples, so that the connector is now rendered unselectable by any other second selector until both subscribers have replaced their receivers, which will be hereafter more fully explained.

The two subscribers A and B are now in conversation, circuit being traced from substation A to substation B by means of the heavily niarked conductors and condensers 814-82 .through the exchange, talking battery being supplied to the callin line through the impedances of relays '7d- 5 and to the called line through the impedances of relay 117 at the connector.

When the subscribers have finished their conversation, they replace their receivers upon the hook levers, 4the act ofsubscriber 'B in so doing restores the connector -G to normal, while the act of subscriber A in so doing, restores line selectbrD, first se' lector l-.Il andv second selector; F to normal. The purpose of dividing the control of the release in this manner may be seated as fol- 4wipers 105-106-107 of connector G to.

leave "conta/cts 6-7-8 of the called line, it would result that upon the breaking of contact 105-6, cut-orelay 12 of the called line would be denergized and upo'fbe retraction of, its armatures, the substation'receiver at B being olf the hook, relay 9 of the called line would be energized causing the selection 'of the line by. one of the associated line se-` lectors. The called subscriber B, would of course be replacing his receiver at about this time, and'if he replaced it before the line selector completed the selection, the 'said selector would come to rest in connection with the line, and so remain rendering the line busy against in-coming calls, etc.

Were the called subscriber enabled, by replacing the receiver, to restore all of the switches used in the connection including the line selector connected to the calling line, the inconvenience pointed out in the preceding paragraph would be duplicated. y

In consequence of the division of the release operations indicated, the armature 122 and its grounded alternate contact is provided which is elfective as soon as a calledV subscriber answers, to lace d second ground upon contact '99 of t e connector and its 110 f already connected tocalled liue B. It will 120 be `thus .seen thatalthough subscriber B has independentv control of the restoration of switch G and subscriber A hasindependent control of the releaseof theothcr switches,

DLE andF, the copcration'of both is re- 125 vqtllnred tol remove the busyptential from e private contact 99 'oftheconnecton 1 will now trac/e infdetail the release o eration occurringwhen the subscribers rep ace their receivers. When subscriber vB does so, 13o

cause the the operation et' arm 5 of the hook lever upon its associated contact springs, momentarily grounds limbs P and S in the usual manner, but this operation is not used to release at the called substation. The replacing of the receiver causes the hook lever to disengage its alternate Contact opening circuit through relay 117, held Venergized by current over the lineduring 00nversation. The upper armature of rela 117 then falls back, and completes a en :it through release magnet RM frorv` giu nd through contact 120 of relay 118, upper armature contact of relay 117 to battery, effecting the energization 4of the release magnet whose' armature is thus attracted, shifts the switchs rings 110-111 to normal opening the circuit of relays 109, 113 and 118 causing theirfdenergizations. The deenergization of relay 118 opened' the circuit of the release magnet RM whose armature thereu ion is retracted and wipers 105-106- 10T al on'cd to return to normal, their restoration causing, on its completion, the shiftin r to normal of the primary 'off-normal switclti` QP. O. Sw the secondary olf-normal switch springs S, O. Swa being restored at the time theiripershave been restored `as to their secondary movements. lVhen the alling subscriber replaces his receiver, ann 5 temporarily rounds limbs 'P and S of the line, the groan ing of limb S short-circuiting the upper winding of differential release relay lower winding of said relay to ground at e substation, its armature is attracted to complete circuit through 'release magnet BM at switch D; from ground, attracted armature of relay Tel, release switch E to battery, The attracted right hand armature of release magnet RM closes circuit through release magnet RML'at second selector F from gro shifted primary olf-normal switch P. 0. SW2 contact, contact 8659, attracted armatureof RM." to battery. The release magnets of all the switches D, E and F, are now ener rized and their energizations shift tonorma :the various release switches RSw, BSW, the shiftinggof said switchescansing respectively the efirgizations ot' relays 48,

R and BH2, whereby the wipers `ot the various switches are disconnected frombuttory and so held during the release of the switches. In the restoration leverat substation-A, arm 5 passing from y the top of its associated contact spring, reu moves,` groundv from the two limbs of "line and the armature of Q relay 74 *returns4 to normal denergizing release magnets RM and RM', the. denergization of RM' opening the circuit of RM. a denergizations of the various release mag- M3, cause the restera J4, and, current' continuing through the und through the.

RSw. and` of the hook i wipers of the various switchesA B5-84 rel switches have reached normal as to thei secondary movements, the secondary o normal switches S. O. Sw, S. 0. Sw and W2 are restored; when the wipers have been restored as to their primary movements, the rimary olf-normal switches P. O. Sw, I. (Il) Sw and P. O. Sware restored. The restoration of the primary oE-normal switches respeetivel cause the denergizations of relays 48, B and BR", rostablishing thel normal connections of the wipers. It should be noted that the armt1- tures of RM when attracted keep the line lin-lbs P-S mnnected to the windings of relay 74, while the ener 'ization of relay 48 by arnmture 50 holds re ay 12 energized,

Assuming now that, at the time Wipers 105, 106 und 107 came to rest engaging contarts 6, 'i' and 8 of thel called line, this line was a bueyjline.y In such case, ground will. be connecte to contact 6 and its multiples ria the shifted test switch TSW, contact 110 of another connector (if the busy Vline be a called line), or ria armature 13 pertaining to the busy lille, its contact 20, wiper 2l of a line selector then connected thereto, to ground through contact 50 at the said line selector (if the busy line be a calling line). In either case, upon the energization of the test relay TR at switch G, as before described` the said relay, instead of being Vthereon denergized, will have its amature locked' in their attracted positions by current from grounded' contact 6, Wiper 105, normal Contact 110, contact 104, rightarmature of relay TR, its right, winding to bat,- tery. The test-'switch contacts therefore remain at normal and a busy signal is transmitted to the calling subscriber from` interrupter 1 through the .induction coil and condenser, left armature of rela TR, normal contact of lower armature ofyrela 109, to the left oper the talking circuit indicated by wit-h which the' are associated. When tli 'heavy lines to switch'E, via normal Contact' 70, condenser 83, to the left over the heavily nrarked talking conductor, .limb S of the line of A. through the transmitter and the primary'of the induction coil. causing an audible si `iai in the receiver, returning over .hmb to the right over the upper talking conductor, normal contact 5l, normal contact of relay T3, armature 55, relay PR through battery B. The calling subscriber, in respense to this signal, replaces his receiver, momentarily grounding the two limbs of his line. Inaslnuch as relay 73 has not been en aol ergized, relays PR and ySR are still o erf,-

al'ively connected to line limbs P and spectively and they grounding of the line reare therefore, ou the limbs, both simultaneonsly energized to close contact Bt-85. Circuit is then completed from ground at re-` lease magnet RM of the line selector, contact ease magnet RM of the Bret ae- `ture of RM2 closes circuit from ground through RM3 at the connector, normal contact 122, the shifted -contact of primary 0i, normal switch P. O. Sw", contact 99-93 attracted armature of RM2 to battery. 7The armatures of all the release magnets are now attracted; and when ground is removed from the two line limbs at substation A, the resulting de'e'nergization -of relays PR-and SR allows contact 84--85 to be opened, .de-l energizing RM and RM; the denergizatlon of the latter denergizing RM2; the denergization of RM2 denergizng RMa; and each switch is restored as its release magnetRM, RM', etc., is denergized. Thus it 1s seen that until the called subscriber answers the call, the release cf, the connector remains under the cont of the calli subscriber the instrumentality cont-rolled y the called subscriber for removing the calling subscribers controlof RM, consists of armature spring 1220i relay 118, which, when'aetuated,by di 'ng its normal contact, o a contact in t e circuit of IRMB and thereafter puts the second busy potential upon contact 99, as before described. From the release operations already described, it is apparent that astsbon as the line selector has selected his linlthe calling subscriber may by grounding the two. line limbssimultaneously cause the closure of contact Sti-84, which will be elective to release whatever switches are connected to his line,4 so that, whatever stage of completing a connecton may have been reached, the release of all switches so far operated may be secured. A

As before indicated, it 'may sometimes happen that a line selector will over-run on its primary or secondary movement throu h accldentV or certain rarely occurring com i- Vnations of circumstances. To take care of these occurrences, I have provided the two switch springs 43 and 53; the former .being sol-elated to the switch mechanism that, if the switch shall make an eleventh primary movement, the contact 43 will be closed;

.while ifthc Vswitch makes an eleventh step in its secondary movement, the contact of 53 will 'closed` In either case, a circuit will be cmpleted from ground through the release magnet RM, contact 43 or 53, as the case may be, alternate contact 47 of therelease switch BSW to battery, energizing re-` lease magnet RM, upon whose energization therelease switch RSW will be shifted to normal, `spring 47 then openingIr the circuit of release magnet RM, whose denergization causes the restoration of the line selector.

Vas follows; Assumin Referring to armatures 78 ana 80 of switch E controlled by relay 76: Their function is to take care of certain difficulties which might occur were they omitted, being scriber has answere the call, causing the ener ization a-f relay 76, then it will be remem ered that current flows from Vground at E upper windings of rela'ys 74-75, attracted armature 56, attracted armature 79, over the'talkingcircuit to limb S, returning over limb '.P, attracted armatures 76 and 63, to battery through the lower windings of relays 75 and 74. lIt is thus seen that the circuit energizing relay 75 is traced through its own armatures 56 and 63 and the calling line. t Assuming that during conversation the 'calling subscriber accidentally moves his dial 1 from normal, the resulting opening of his line circuit at contact 4 would denergize relay 75; its armatures 56 and 63 would fall back; and when the line at. A was again closed conductively, relay 75 would continue denergized so that when the subscriber replaced his receiver, dierential release relay 74 would be out of operative relation with his line. Armature contacts 78 and 80 are therefore provided, controlled by relay 76 f (which is only denergized when the release of the first selector' actually occurs) establishing, when attracted, a parallel path for current through `the windings `oi relays 74 and 75, the armatures 56 and 63 being exclulded from this circuit so that an accidental opening of the line circuit at' the'substation,

that. the called subof the calling subscriber, causing temporarily the 'denergization of relay 75, does not put the central otlice apparatus in such condition as to prevent the said relay 75 from becoming again energized when the substation circuit is again closed.

Referring now to the mechanical drawings, as shown in Fig. 2, a preferred form of the master switch, the contacts '31 and 35 are the terminals of the ljne selectors, while the contacts 30v and 34 extend around under the respective rows of contacts 31 and 35, the wipers 30 and 34 (Figs. 2 and 3) havan mt'errupter actuated by its armature, as

shown.

A line vselector (Figs 4 7, 8 to 1-1 inclu-,

sive),qcomprises essentially ten group contacts 26 and a group wiper 27,1naling primary movements only, a contact' bank `iny cluding one hundred sets of contacts 22, 20,

'ing in themselves no circuit connections, be-

24, arranged in ten groups of ten sets of contacts each, a set of wipers 23, 25, 21, capable of primary movements to select a group and secondary movements in an y intersecting plane to select a contact set of a group, a primary olf-normal switch P. O. Sw comprising switch springs shifted on the first left is given iii Fig. 9 and a front View in Fig. 10, a Contact set 22, 20, 24 (Fig. 9) bcing indicated by a single short line in Fig. 10. The one hundred sets of contacts, as indicated in Fig. 10, are arranged asvif projectin through the inner surface of a section oa hollow sphere.

In their primary movements, the wipers 23, 25, 21 are rotated step-by-step from left to right, each step bringing them opposite a different group orupright section of ten contact sets; and in their secondary movements, the wipers are rotated step-by-step upward over the contact sets of the selected row, successively engaging them.

The wipers are pivoted at 23b to a bearing 23, clamped to arotatable primary shaft PS suitably journaled 'to the main frame; while a rearwardly extending portion of the Wipers,provided with a roller, engages a broad piece 160 fastened to the secondary shaft SS. the secondarvinovements of the wiper ends heilig effected by the downward movementof shaft SS` piece 160 rotating the wipers about the pivot at 23". Y

A suitable spring 161 is fastened tothe primary shaft PS against whose tension it is turned, while spring 23 is fastened to the wipers against whose tension the secondary movements are performed.' Thesel springs serve, when the switch (by the with drawal of the retaining detents hereafter described) is released, to restorethe primary and secondary shafts and consequently the wipers.

The auxiliary or group selecting wiper 27 is fastened to the primary shaft, being solely controlled thereby, and has its row of group contacts 26.` l

The primary off-normal switch P. O. Sw comprises an arm fastened to the primary shaft and provided with a stud of insulat in material, as best shown in the top View (Iig. 8), holding springs 42, 41 and 40 in their normal positions, shaft PS under' the influence of spring 161 pressing the stud against spring 42. rThe first step of the shaft, which 1s clockwise, moves the stud away7 from spring 42 and the three springs 42, 41 and 40, by their own tension, are shifted to the alternate position.

The operation of the rimary over-run switch will be understoodp from an inspection of Fig. 7, wherein shaft PS is at normal. The movement of the shaft in the operation of the switch is clockwise, and stud 43a on' thel eleventh clockwise step of shaft PS comes against and presses the spring 43 ofV the primary over-run switch to engage its alternate contact.

The secondary olf-normal switch is best shown at S. O. Sw in Fig. 10 comprising an arm clamped to secondary shaft SS extending to the right to hold, in its normal raised position, a-stud of insulating material extcnding1through the switch frame and engaging the., secondary 'off normal switch springs-44 and'45. With the first step of secondary shaft BSS, downward in direction, the arm of the secondary olf-normal switch is brought downwardly so that springs 44 and 45 press the stud down and engage their alternate contacts.

The secondary over-run switch comprises the stud 53 fastened to secondary shaft SS and so placed that on the eleventh secondary movement it engages spring 53 and presses it into engagement with its associated contact.`

` For rotating the primary shaft PS, a circlear ratchet 124 (Fig. 4) is provided, adapted to be turned step-by-step by the armature-driven pawl 123 of primary magnet PM, whose vibratory circuit-breaker is indicated at 126.

As well shown in Fig. 9, the secondary shaft SS has cut on its inner surface a ratchet adapted Jo be engaged by the armaturedriven pawl 127 of secondary magnet SM, by successive thrusts of may be moved downwardly. The secondary magnethas, like the primary magnet, its armature-actuated circuit-breaker.

A pivoted retaining detent is provided for each shaft, that of the primary shaft being indicated at 125 of ig. 4.and that of the secondary shaft at 128 (Figs. 4 and 11). These deteuts have rearwardly extending which-theJshaft portions normally engaged by orifices in re hook at one end ofarm 131.

in whatever position theymay be ygrlaeedby` the rimay or secondary magnetsliw.; 3 y."

Tie release switch springs 46 and4'4 gig. 11) are heldin their normal o'sitions y a `he first actu' ation of primary magnet PM, by o erating arm 132, tilts the right end of arm 1 1 down,

4 spring 46 is released and the two springs 46 ary steps until a and 47 by their tension move to engage their alternate contacts.

`The release magnet RM has (as best shown in Fig. 11) a pivoted arm 130 whose left end an associated springtends to deress. 0n attraction of the armature of M, arm 130 is drawn to the left, two orifices therein (shown in the top view, Fig. 4) slipping over the rearwardly extending portions of detents 125 and 128. At the same time the button of insulating material on the ri ht end of arm 130 restores sprin 46 and 4g by engagin spring 46 to move 1t to be caught and held by the hook of arm 131'. When magnet RM is now denergized; its retracted amature draws arm 130 to the right, which, keeping.l its hold on detents 125 and v128, moves t em away from their shaft ratchets so that the shafts are now free to be restored, shaft SS b s rin 23 fastened to the wipers, and s a t P by spring 161. f

A spline 170 (Fig'is. 4 and 9) is provided on the secondary s aft engaging with the first movement thereof any ad'acent tooth of ratchet 124 to hold the prlmary shaft against return movement to the end that on the restoration of the shafts as, described, the secondary shaft may be first completely restored clearing the wlpers from the bank, whereon spline 170 re eases the primary shaft and permits its restoration.

yThe primary and secondary onorgnlal switches are of course restored byI the 1espective shafts when they reach normal, the restoration of the secondary one occurring first.

Recapitulating the principal operations; the first actuation of primary magnet PM rotates the wipers a step, shifts the primary olf-normal swltch releases the rimary and secondary shaft detents and s fts the release switch. Subsequent actuationsof said magnet serve only to advance the wipers successive primary steps, until a possible eleventh step when the over-run switch is shifted. y

The first actuation of secondary ma et SM advances the line wipers a secon ary step, shifts the secondary olf-normal switch, and interlocks spline 170 with ratchet. 124. Additional actuations of said magnet mcretliy advance the line wipers additional secon possible eleventh step when the secondary over-run switch will be shifted.

The release magnet when energized shifts the release switch to normal, and when deenergzed withdraws the shaft detents, re.

storing the switch.

i The mechanism associated with magnet 77 of Fig. 1, Part 1, is shown in detail in the top view (Fig. 15). Vslt includes the suitablyv pivoted feed-spool 145 carrying a .supply of inked ribbon 153 and record ribbon 152 which may be of paper in alternate layers, and the receiving-spool 140 to which 1s fastened ratchet 141,0 erated, to wind the ribbons off the feed-spoo onto the receivingspool, by the pawl 142 fastened to arm 150 upon armature 143,1the attraction of said armature serving to draw pawl 142 to the left to engage the next tooth of ratchet 141, so that, -on the retraction of the armature, ptawl 142, rotates ratchet 141 and spool 140 a s ep. y

Armature 143 carries a hammer piece 144 whose momentum is eiective on the attraction of 143, to give a rebounding blow u on the portions of ribbons 153 and 152 t at are adjacent to the hammer, printing upon record ribbon 152 whatever number upon the curved ty eframe 146 may, by the operation of t e line selector, have been 'brought opposite the hammer 144.

The general conformationV of type frame 146 and its ,association with the primary and secondary shafts will be seen in Fig. 15 and Figs. 9, 10 and ll'.

he cylindrical bearing of frame 146 isv splined to primary shaft PS (as shown in Fig. 15) so that it is rotated with the shaft, but is free to move down and up thereon.

The lower edge of the frame 146 is pressed against a pro]ection 149 on secondary shaft SS (Fig. 15) by a spiral sprin 147 shown in Figs. 9,- 10 and 11, tothe en that when shaft SS- 1s worked downwardly in the o'peration of the line selector, spring 149 may move the typeframe 146 a corresponding lextent'. downward.

The type numbers corresponding to the respective tens and units values of the subscrlbers lines in their respective` hundreds areto secure greater spacing, preferably arranged in 'ten vertically disposed double columns, as indicated in Figs. 10 and 411, numbers 11,12,. 13, 14, etc.,l comprising a double column.

Assumn that subscriber 9924 makes a call, the primary shaft SS of the line selector, Fig. 12, makes of course two rotary ste which bring the column of numbers inc uding 21, 22, 23, etc., to a positibn di rectly above the hammer end 151, (Fig. 15). The secondary shaft SS then makes four downward steps to brin the wipers to connect with the contacts o the line and spring 147 causes the type frame `to descend correspondingly, number 24 being thereby brought directly opposite the end 151 ot' l hammer 144. imilarly, if any other subscriber makes a call, the line selector operating will, with the adjustment of its wipers, `move its type frame so that the type number correspondingr to the number of the calling line is adjusted to the hammer. When a line selector is resto|ed,its shafts of course restore vthe type frame to normal.

Telephone subscribers on measured ser ire are usuallyeharged only` for such calls as are answered, and to conform to this praetice I have so arranged the circuits of my system that print-ing magnet 77 is only op- 16 erated in case and at the moment when the called subscriber responds. At that time it will of course`ret'ord the number of the call in subscriber on ribbon 152. W'hen' the calling subscriber at the end of conversa i 20 tion causes the first selector to be restored.

magret 77 is glenergzcd and pawl 112. turning spool 140, brings fresh spaces ol ribbon in front of hammer end 151 ready lo print the next'number.

Since the line selrctors belong to aparticular one hundred lines, it is necessary. in order to et a permanent printed record of each completed callloversa linekto place upon the type frames of the ten line selectors only the last two digitsof cach subscribers number, the line selector itself in dit-ating the thousands and hundreds digit.

It is apparent that only one thousand call recorders are required for ten thousand suhscribers lines, a material savingr over recorders individual to lines.

The mechanism of the lirst'selector is, in

eneral similar to that of the line selector. he vibratory interruptor of the primary 40 mpg-net and the measured service mechanism are omitted.

The primary oil-normal, secondary olfnormal and release switches are controlled in a manner similar to those of the line selector, and the adjustment of the line Wipers is mechanically similar. 'lhe spring combinations of the various off-normal and redase switches correspond of course to those 1 dieated at E in Fig. 1.

In Figs. 5 and 6 is shown thtl mechanisln associated with the first Selector for shifting springsl'l. 54 and 72, 62, described in connection with F ig. 1. Said springs are mounted as indicated in' F ig. 5, the View showing the slirings at normal. The tivo insulated studs ll'are drawn to the Aleft to shift the springs, and when they are freed the tension ol the springs restores the studs and springs. The studs 135 are .fastened to an arm 134 (Fig. (i). pivotcd as shown, and having' a small prdjerton on itsy lower extremity adapted to be engaged by the hook ol arm l-ll when :he armature of magnet 73 is attracted. Then said mag* net is thereafter denegiz'wl on the rc` spouse of the called subscriber, its retracted armature causes arm 133 to draw the lower portion of member 13-1 to thc right, whereby studs 135 move to the left to shift their springs. Y The operation of release magnet RM is similar to that of magnet RM of the line selector, except that its armature carries an "arm 136 adapted, when the armature is attracted, to engage and lift hooked arm 133 75 free of member 134, thus allowing the restoration of studs 135.

lt will he remembered that the shifting ot' spring 72 (see Fig.V 1) energizes relay 76, a hose energizntion causes that of the printing magnet 77. The latter should preterahly not be operated when a calling subscriber has connected his line with an idle walled line and fails to secure an answer. Under such circumstances, magnet 73 is 85 energized as soon as connection is made with the called line, and its denergization follows when the calling subscriber replaces his receiver. causing the energization of release magnet RM', `which, by shifting spring 90 BSW', encrgizes relay BR whose armature opens the crenit of magnet 73. The previous energization of 73 has caused arm 133 to engage member 134 (see Fig. 6). The energization of magnet RM', preceding the 95 denergization of magnet (3, is e'ective to cause arm 136 to`lft arm 133 free so that the denergizaton of magnet 73 (occurring while magnetyL'HM remains energized) is ineliective to` move member 134; spring 72 10o and the otherassociated springs remaining at normal, whereby an improper operation ol magnet 7,7 is avoided. A

The second selector is mechanicellylsimilar to the first selector, except that magnet` 73 is not employed, the various off-normal and release spring combinations being ar ranged as indicated at F in Fig. 1.

The connector shown in Figs. 12-1314 inclusive is generally similar to the first selector. No vibrator `eiInuit-breaker of the serourlaiy magnet Sid is provided end the positions of the wipers with respect to the Contact bank is such that two secondary steps are. required to cause the wi ers to engage the first contact set of a se ected row 'for the purposes hereinbefore indicated.

l ThrI mechanism nftest relay TR is best shown in Fig. 14. Tht test switch`springs 11G-111 are preferably' vertically disposed 120 and arm 137, carried by the armature of relay TR, has a raised portion adapted, when the arn1ature-is attracted, to clear spring 111,"the spring associated with arm v137 then causing the upraise to engage said 125 spring 111. On the delinergization of relay TR2 the springs 111 and 110 are of course' shifted by arm 137v for the purposes hereinhetore indicated. When release magnet RM attracts its armature, pieceV 138 as- 196 

